Car coupler



April 1960 w. J. METZGER 2,931,518

Y CAR COUPLER med July 17 1958 3 Sheets-Sheet 1 N UNCoUPL/NG g DISPLACEMENT Q CuRvE W '96 \l 5 Longitudinal ENTOR.

' WILLIAM J. METZGER April 5, 1960 Filed July 17, 1958 CONVENTIONAL Coup. ING

IMPROVED COUPLING Stage A w. J. METZGER CAR COUPLER Stage 3 Sheets-Sheet 2 mmvrox.

W/LL/AM J. METZGER BY April 5, 1960 CAR COUPLER 1 Filed July 17, 1958 w. J. ME'rzsEk 2,931,518

Ufl t t s Peter CAR COUPLER William 3. Metzger, East Cleveland, Ohio, assignor to Nationm Malleable and Steel Castings Company, Cleveland, Ohio, a corporation of Ohio Application July 17, 1953, Serial No. 749,187

4 Claims. (Cl. 213-451) The present invention relates to knuckle couplers, such as the type E coupler approved by. the Association of American Railroads (A.A.R.) for heavy-duty freight service on American railroads, utilizing the well-known IO-A contour. Couplers of this general type are characterized by their accommodation of vertical slip movements of one coupler relative to the other in a coupling, and vertical angling within the coupling without vertical angling of either coupler thereof relative to its associated railway vehicle.

On account of its relatively low cost, strength and dependability, the type E coupler has been regarded in the United States as the standard coupler for interchange service in freight use. Strangely, however, the use of the E type coupler has been restricted to service on relatively heavy cars of the type used by the public carrier railroads. There has been a lack of serious effort to adapt this coupler, or the other l-A contour types, to substantially lighter railway vehicles, such as some of those in use in private industry. Recent attempts to equip and use lightweight cars equipped with these couplers proved unsatisfactory because of the difliculty and often the failure encountered in separating the cars.

It was observed that such failure occurred principally when the cars were relatively light in weight and were empty, thus suggesting that the mass of the empty cars provided insufficient inertia force for uncoupling. As there was no explanation for the failure to uncouple, on a strictly frictional basis, it became apparent that there was an inherent defect in the standard l0-A contour as found in the A.A.R. approved standard E coupler, which caused binding of the knuckle noses during an uncoupling operation.

The A contour was adopted as standard for the type E coupler in 1933 by the Association of American Railroads to replace the older 10" contour. The modifications of the older contour providing the l0-A contour are taught in principle by the Kinne Patents Nos.

2,007,450, 2,007,451, and 2,007,452, although the Kinne teachings are considerably abridged in the present l0-A contour, as specified in the ofiicial A.A.R. volume entitled Proceedings, Division 5, Mechanical 1933 to 1935, Inclusive. Inherent in the modifications taught by Kinne, particularly those resulting in a tighter contour, was the tendency of couplers embodying the 10-A contour to resist uncoupling.

The Metzger Patent No. 2,245,043 is concerned with a knuckle binding problem in tightlock couplers but this patent does not provide a solution of the present problem because it concerns a fundamentally different coupler contour. In the tightlock coupler, there is normally no free slack for a mating coupler knuckle. In uncoupling two tightlock couplers, the knuckles complete separation essentially by relative pivoting of the knuckles, i.e., an inner tail surface of the unlocked knuckle engages and pivots about a vertical ridge on the front face of the locked knuckle. Such a ridge is characteristic of the tightlock knuckle. The 10-A contour provides no analogous ridge, and to relieve the lateral tail surface and to fill in the throat surface of the knuckle of a l0-A contour coupler at a point as taught in the prior Metzger patent with respect to the tightlock coupler, does not eliminate the resistance to uncoupling mentioned above.

Hence, an important object of the present invention is to improve the uncoupling action of the standard freight car coupler presently manufactured for the US. railways, whereby it may be used on lighter weight cars without failure to uncouple.

Another object is to accomplish the foregoing object without weakening the coupler as a whole or increasing its free slack.

A further object is to increase the versatility and field These objects and the various features and advantages of the invention will become apparent in describing the present invention, which resides essentially in a changed outline of the inwardly-facing lateral surface of a knuckle for couplers having the 10-A contour.

' The coupler of the invention comprises a conventional lit-A contour head having a front or buffing face and a knuckle modified with respect to the 10-A contour, having a nose and a tail section in fixed angular relation with the nose extending at locked position crosswise of the longitudinal axis of the coupler in forwardly spaced relation with the front face to provide a pocket for receiving the knuckle nose of a mating coupler. The rear surface of the nose and a portion of the front face forming the pocket are complementary to the rear and front surfaces, respectively, of the nose of another similar coupler mated therewith. In the modified 10-A contour of this invention, the rear surface of the knuckle and the front face portion are connected by a laterally-facing longitudinal surface of the head to form the closed end of the pocket, and are spaced thereby to provide free slack for vertical angling of coupled couplers in normal railway use without appreciable vertical angling of the couplers relative to associated railway vehicles. The knuckle has a concave throat area curving rearwardly from .a juncture with its aforementioned rearwardly facing surface and a laterally facing surface extending rearwardly from the throat area to provide a lateral face of ,the til section of the knuckle. A rear portion of the throat area and the forward portion of the lateral surface are in fiush-to-undercut relation with the vertically adjacent longitudinal head or pocket surface at the buff position of the knuckle. On a knuckle having a tail portion providing a lock-supporting shell, the lateral knuckle surface may be approximately straight in a rearward direction and with a rear portion of this surface forming a lateral face of the shelf.

In the accompanying drawing illustrating the invention:

Fig. l is a sectional plan view of a coupling comprising two E couplers in bufi relationship;

Fig. 2 is a fragmentary plan view of a knuckle in ac cordance with the invention, illustrated in full line with deviation from the prior art contour illustrated in dotdash;

,Fig. 3 is a diagram illustrating the respective paths of departure followed by unlocked prior art and improved couplers supported for free lateral movement when separated from locked rigidly supported mating couplers;

Fig. 4 is a diagrammatic plan view of prior art couplers illustrating relative positions at the stage of uncoupling in which they normally bind; I Fig. 5 is a diagrammatic plan view of improved couplers embodying the invention illustrating a stage of uncoupling approximating that shown in Fig. 4; and

Fig. 6 is a diagrammatic plan view illustrating the Patented Apr. 5, 1960 couplers of Fig. at a later stage of uncoupling in which the knuckle noses are about to separate.

Fig. 7 is an elevation in section of coupler B taken along line VII-VII of Fig. 1. a

Fig. 8 is an elevation in section of coupler B taken along line VIIIVIII of Fig. 6.

Fig. 1 illustrates two E type couplers A and B in coupled buff relationship. These couplers may be constructed in all respect in accordance with the specifications of the Association of American Railroads, except for the knuckles 1A and 1B. As the construction of the heads 2A and 2B and the locks 3A and 3B is well-known and the details thereof may be found in Metzger Patent No. 2,617,540 (Re. 23,796) and the A.A.R. publication Proceedings, Division J, Mechanical, 1933 to 1935, Inclusive, the detailed description of the invention will be concerned primarily with the structure of the knuckles 1A and 1B which differ from the standard only in the contour of their inner lateral surfaces (see Fig. 2). It is further understood that the standard 10-A contour coupler includes both knuckle and coupler head surfaces, as illustrated in the lower left corner of page 19 of a circular The A.A.R. Standard E Coupler of June 1939, published by the Association of American Railroads and available from any one of the standard coupler manufacturers in the United States.

In Fig. 1 it is apparent that the surfaces of the head 2A which contribute to the standard 10-A contour, viz., front face 5, concave corner surface 6, and longitudinal vertical surface 4 are closely complementary to a front surface 9, convex corner surface 16, and a lateral nose surface 11 of the knuckle 113 also within the modified 10-A contour. The 10-A contour is the coupler-receiving profile (as outlined by an overhead view) of vertical surfaces of a IO-A type coupler adapted for mating opposing relation With the corresponding surfaces of another l0-A contour coupler. Fig. 1 also shows that the rear surfaces 12 of both knuckle noses are closely complementary and, in the buff position of the couplers, form a clearance 14 having a width which may be measured parallel to the longitudinal coupling axis YY of the couplers. The magnitude of this width is approximately uniform regardless of the distance along the length of the clearance 14 from the Y axis at which the width is measured. Hence, in buff operation, the forward and lateral nose surfaces attain substantial mating relation with the surfaces 5, 6, and 4 of the head; in draft, the rear nose surfaces 12 of the knuckles attain mating relation with the nose surface 11 mating closely with the vertical and longitudinal head surface 4.

Referring now to Fig. 2 for better detail, the throat of the knuckle 2 is shown as a rearwardly and laterally facing concave area or surface 7 comprising two contiguous arcs of different radii III, VI and joining at its forward end at point M with a short straight surface 15 on the nose portion. This straight surface joins also with an adjacent convex nose surface 16. At its rearward end the throat surface 7 joins with the laterally facing longitudinal rearwardly extending knuckle surface 17 at point N. The arcs forming the surface 7 connect substantially along a tangent without the development of any convexity. Points M and N are determined by the extreme limits of the concavity of surface 7.

, Fig. 2 also shows the prior art contour of the knuckle 2 indicated by the dot-dash line as comprising portions 17a, point N, and the short arcuate section 7a just immediately forward of the point N. As the prior art couplers of Fig. 4 indicate, the prior art surfaces 17a and 7a protruded in draft position laterally outwardly beyond vertical alignment with the head surface 6 into the knuckle-receiving pocket. This was also true, to a slightly lesser extent, in the buff position of the knuckle. As illustrated in Fig. 1, this invention changes the contour of the knuckle to dispose a forward portion of the surface 17 and a rearward portion of the concave surface 7, including the junction of these two surfaces at N in recessed relation with the prior art contour comprising the surfaces 17a and 7a, and to place surfaces 7 and 17 in undercut relation with the longitudinal laterally-facing head surface 4 at the buff position of the knuckle.

The surface 17 extends in straight line contour from point N to the curved surface of the corner 19 of the lock-supporting shelf 20. Although essential that the forward part of the surface 17 be depressed from the prior art contour to point N, it is not critical that the rear portion of surface 17 be disposed inwardly of the prior art outline 17a from the standpoint of eliminating binding of the knuckles as they disengage during uncoupling. However, the surface 17 is extended in straight line direction to the corner 19 primarily to facilitate the manufacture of the knuckle and to provide clean design. The shelf 29 is in the form of a lug protruding laterally from the main body 21 of the knuckle, as found in many conventional knuckle couplers. The upper surface 22 of the shelf is aligned horizontally in the normal position of the coupler at a level of perhaps a couple of inches below the uppermost surface of the knuckle tail.

In order to precisely distinguish this invention from the conventional 10-A couplers and to facilitate reproduction of the invention in a manner for achieving the results available therefrom, the dimensions for developing the innerlateral contour of the knuckle along with the analogous dimensions of the conventional 10-A contour knuckle are presented in Table A below. In the dimension column of this table, the numerals including the prime mark designate dimensions of the conventional knuckle. The greater portion of these dimensions locate the striking points for the radii for generating curved surfaces with respect to the longitudinal axis Y-Y and a transverse standard construction axis XX of the coupler used by the industry. The axis XX is located rearward of a transverse tangent Z to the front face 9 of the knuckle in accordance with dimension VIII. Such dimensions may vary, in general, within plus or minus 0.01 inch.

Dimension IX, which cannot be properly included in Table A, is the distance between the new knuckle contourat point N and the old contour line 17a. In the embodiment described, dimension IX is approximately A; inch.

As the improved knuckle to which the above table relates may conform in all other dimensions to the conventional 10-.A contour knuckle, further dimensional data may be obtained from the ofiicial publication of the Association of American Railroads, entitled Proceedings, Division 5, Mechanical 1933 to 1935, Inclusive.

'Fig. 4 attempts to depict the difficulty which occurs in the uncoupling of the prior art 10-A contour type couplers. The couplers A' and B are shown at an intermediate stage in the disengagement of the knuckles 25 and 26. At this instant, the throat of the knuckle 26 may be assumed as being rotated around the nose of the knuckle 25, but in doing so, excessive interference of the rearwardly protruding portions of the noses occurs at point D. This interference is aggravated by a wedging" action which occurs at point F 'whereat a roundedfor ward corner surface of the nose 25 is being engaged in high frictional pressure against a surface of the knuckle 26 occurring approximately-at the juncture of the throat portion 7a and its lateral tail surface 17a- By the present in'vention, the inner lateral surface of the conventional knuckles has been relieved at this point to allow engagement of the nose of the locked knuckle with the throat of the unlocked knuckle to take place along throat areas further forward in the throat of the unlocked knuckle at the stage shown in Figs. 4 and 5. The latter figure illustrates the knuckles of this invention engaging at approximately point H which is substantially further forwardly in the throat of the knuckle 1A than that occurring at the same stage of'knucklev opening shown in Fig. 4 (conventional couplers).

In the coupling of Fig. 5, there is no development points of binding corresponding to points F and D of Fig. 4. In bringing about this invention, it has been recognized, looking now at Fig. 5, that the throat of the unlocked knuckle 1A of coupler A and the nose'of the knuckle 1B of the locked coupler B must function in the early stages of uncoupling in the manner of a solid half bearing and a journal, respectively, and that the knuckles should be shaped accordingly for the early stages of uncoupling, wherein the relative movement of the knuckles is essentially rotary. Subsequent to the rotary phase, the nose of knuckle 1A, as the result of being opened by a longitudinal draft force, revolves about an axis established by the knuckle pin 22 to separate its throat from the nose of the knuckle 13. During this latter intermediate stage, the relative motion of the knuckles is a combination of rotary, longitudinal and lateral.

On account of the larger radius of curvature at the rear of the throat 7 than at the front (see dimensions III and VI, Table A) and the fact that radius III is larger than radius III of the conventional knuckle, a slight clearance is maintained between the area comprising the rear portion of the throat surface 7 and the lateral tail surface 17 of knuckle 1A, and the forward nose surface of the knuckle 1B.

Observing the coupler B as shown in Figs. and 6, the knuckle occupies its normal position for draft operation. In contrast with the undercut relation of the knuckle tail with the head surface 4, as shown in Fig. 1, a knuckle surface comprising a forward section of the surface 17 and a rearward section of the concave surface 7 is offset slightly outwardly into the knuckle-receiving pocket of the coupler B at the draft position of the knuckle 1B. Hence, in the embodiment illustrated, the recessing of the lateral tail surface, as taught herein, is related to the slack or backlash allowed between the sides of the knuckle tail and the lock 3B or the side wall 20 to produce the aforementioned undercut relationship of Fig. 1 (buff position) and the protruding relationship of Figs. 5 and 6 (draft position). Such slackness is shown between the lock 3B and the knuckle 1B of Fig. 1 and is ordinarily of the order of A inch in a 10-A contour coupler. The foregoing is a desirable relationship since greater recessing of the inboard side of the unlocked knuckle A would, if substantial, lower the knuckleclosing efficiency of the couplers in coupling operations.

Beyond the stage shown by Fig. 6, all portions of the rear surface of the nose 1A incline forwardly from its throat and the couplers readily separate by cam action as relative longitudinal movement is continued. During this latter stage, most of the relative lateral movement of the coupler heads occurs.

For example, Fig. 3 is a graph illustrating the manner in which uncoupling displacement of a coupler free to move laterally, occurs if the coupler joined therewith is held from moving laterally. This graph embodies path T for a conventional l0-A contour coupler, and path S for an improved 10-A contour coupler having a knuckle shaped as herein taught. It will be noted that the conventional coupler executes a relatively sudden lateral movement during uncoupling, as indicated at section 40 of the curve T, whereas the curve S comprises a relatively gentle lateral swing distributed over a somewhat later period in the uncoupling cycle. The initial and final portions of the cycles of both couplers appear to coincide.

Improvement of the l0-A contour type coupler, as hereinabove described, has rendered this general type of coupler adaptable for use on vehicles such as steel-mill charging buggies and mine cars of substantially less weight than the cars on which this type of coupler is normally used. Furthermore, it eliminates the occasional coupling and uncoupling difiiculties encountered in the use of full-size commercial railway vehicles arising out of the assembly of couplers whose parts are cast to certain undesirable combinations of dimensions approaching the maxima and minima in the dimensional tolerance ranges prescribed therefor. As this invention necessitates no changes in the head and no changes in the front and rear surfaces of the knuckle, the free slack relationships of opposed couplers embodying the invention have not been changed. Hence, though the coupler of the invention is easier to uncouple, it provides as tight a coupling as the conventional couplers. The dimensions with respect to which the invention has been described are critical only in their relativity and not in their magnitude considered individually. As is common practice in the art, with respect to the various types of couplers, the scale of the overall contour established by the invention may be enlarged or reduced with the maintenance of the approximate proportions established by the embodiment herein described.

The terms and expressions which have been employed are used as terms of description and not of limitation and there is no intention of excluding such equivalents of the invention described or of the portions thereof as fall within the purview of the claims.

What is claimed is:

1. In a car coupler construction embodying generally the lO-A contour; a coupler head having a front face; a knuckle having a nose and a tail section, the nose extending in fixed angular relation with the tail section and, at buff position, crosswise of the longitudinal axis of the coupler in forwardly spaced relation with the front face to provide a pocket for receiving the nose of a mating coupler; said knuckle having a concave throat area contiguous with, and extending rearwardly from, the rear surface of the nose into tangency with a side surface of the tail section; a forward portion of the area having a center of curvature approximately 3% inches rearwardly of a tangent to the front face of the knuckleand inch inwardly from the longitudinal axis of the knuckle toward said area, a rear portion of the area having a center of curvature approximately 4 ,5 inches rearwardly of said tangent and about inch outwardly from said axis, said tangent being perpendicular to said axis.

2. In a car coupler construction embodying the 10-A contour; a coupler head having a front face; a knuckle having a nose and a tail section; the nose extending in fixed relatively angular relation with the tail section and, at buff position, crosswise of the longitudinal axis of the coupler in forwardly-spaced relation with the front face to provide a pocket for receiving the nose of the knuckle of a mating coupler; said knuckle having a concave throat area partly forming the rear surface of the nose and extending rearwardly into merging relation with a rearwardly-extending laterally-facing surface of the tail section; said throat area being contoured to receive the nose of a similar coupler in arcuately complementary journalto-bearing relationship for relative rotary movement therebetween in substantially said relationship from a stage corresponding to locked draft position of respective couplers to an open stage of one of the couplers wherein coupler to a direction extending forwardly and away from said head face.

3. In a car coupler construction embodying generally the 10-A contour; a coupler having a front face and a side wall; a knuckle having a nose and a tail section in fixed relatively angular relationship; said knuckle'having a concave throat area contiguous with, and extending rearwardly from, a rear surface of the nose, and merging in a junction with a rearwardly extending, laterally facing surface of the tail section; said throat area being generally complementary to contiguous lateral and rearward surface portions of the nose of a mating coupler; a lock having a locking position confining the tail section between the lock and a side wall of the head; at the locking position of the lock, the knuckle being movable between a buff position wherein one side of its tail section rests against said sidewall and "its other side is spaced from said lock by apredetermined backlash clearance, and a draft position wherein said other side of the tail section rests against the lock and said one side is spaced from the side wallgby said clearance; the junction of said area and said tail surface being disposed in laterally recessed relation with vertically adjacent longitudinally extending, pocket-forming surfaces of the head at said buff position, and in protruding relation with said surfaces at said draft position. a

4. The car coupler construction of claim 3 wherein: said backlash range is not greater than about one-fourth inch.

References Cited in the file of this patent UNITED STATES PATENTS 

